Red Swordtail

Red Swordtail

Red Swordtail (Xiphophorus hellerii) is a classic selectively bred color variety displaying a vivid, solid red body — one of the earliest and most enduring color variants developed from the wild-type Green Swordtail. The Swordtail is one of the most recognizable livebearers in the freshwater hobby — the dramatically elongated lower caudal fin ray of mature males creates an unmistakable sword-like silhouette that has made this fish a staple of community aquariums for over a century. Males are slimmer and more colorful with a fully developed sword; females are deeper-bodied and lack the extension entirely.

Feeding & Care Tip: Sera Vipan Tropical Flakes and Hikari Mini Algae Wafers make excellent daily staples for a balanced omnivore diet — swordtails need both plant matter and protein to maintain color and condition. Supplement 2–3× per week with Hikari Frozen or Freeze-Dried Baby Brine Shrimp, Hikari Frozen Daphnia, or Hikari Vibra Bites. For fry, Sera Micron Fry Food is an ideal first food. Feed small amounts 2–3 times daily. For best red coloration, choose a staple food that contains carotenoids or astaxanthin — these compounds actively deepen and sustain orange and red pigmentation in this variety.

Native to rivers and streams of eastern Mexico and Central America — from Veracruz south through Guatemala, Belize, and Honduras — where it inhabits clear, moderately flowing streams with abundant vegetation. The Red Swordtail is not a wild-type fish; it is a captive-bred color morph produced through deliberate selective breeding, one of the first developed from the wild Green Swordtail stock. It is as hardy and adaptable as its wild ancestors — tolerating a wide range of water conditions — but like all selectively bred color variants, color intensity is best maintained with appropriate diet, stable water, and a tank environment that doesn't stress the fish into suppressing pigmentation.

Keep with two or more females per male — males pursue females persistently, and a single female with no companions to share the attention will be visibly stressed. Male swordtails can also be aggressive toward rival males; if keeping multiple males, provide ample space and plenty of visual barriers. Swordtails are excellent community fish and compatible with most similarly-sized, peaceful species. A tight-fitting lid is important — swordtails are active swimmers and known jumpers, particularly when startled. An interesting and well-documented biological note: female swordtails occasionally undergo natural sex reversal, developing swords and male characteristics later in life — this is entirely normal and not a cause for concern.

Swordtails are prolific livebearers — females produce 20–100 fry every 4–6 weeks, and females store sperm for several months, so a single mating results in multiple broods. Dense planting provides essential cover for fry and helps improve their survival rate alongside adults. Sera Micron Fry Food is an excellent first food for newborn swordtail fry.

Care & Ideal Parameters